Introduction: Bariatric surgery has proven effective in managing obesity. Prehabilitation improves functional and physiological capacity before bariatric surgery. The study aimed to evaluate the change of body composition and functional status following short-term pre habilitation among morbidly obese patients before bariatric surgery . Results: Total of 45 participants were recruited and majority of them were female (71%). The median age was 36.0 years old (OG) and 34.3 years old (SOG). SOG achieved a significant higher median weight loss percentage (-7.4% vs -4%), fat percentage (-4.4% vs -1.7%) and fat mass loss (-9.9kg vs -3.8kg); but OG had a significant better muscle mass (3.2kg vs 2.8kg) as compared to SOG (p<0.001). Both groups showed a significant reduction in waist circumference and improvement in handgrip strength after prehabilitation (p<0.001). Discussion/Conclusion : Coupled with moderate-intensity aerobic exercise, the whey-based VLCHP regime preserves myofibrillar protein synthesis; promotes greater muscle strength and mass; reduces fat mass during negative energy balance periods. The fortnightly prehabilitation might integrate into the routine clinical practice to improve body composition and functional status before bariatric surgery.